SEMEN CHARACTERISTICS OF CROSSBRED (FRIESIAN X SAHIW AL) BULLS AT LIVESTOCK RESEARCH ST A T.lON, NA TIONAL AGRICUL TURAL RESEARCH CENTRE, ISLAMABAD

The aim of the present study was to investigate the. semen characteristics (volume, motility concentration and morphology) of crossbred (Friesian x Sahiwal; F x S) bulls maintained at Livestock Research Station of National Agricultural Research Centre, Islamabad. Moreover, sperm head, mid-piece and tail dimensions in crossbred (F x S) and pure-bred (Friesian and Sahiwal) bulls were also studied. Semen was routinely collected twice a week during the. months of June 1997 to May 1998 from seven crossbred (F x S;.No. 36, 37, 38,39, 40,41 and 42) bulls by means of prewarmed (42 °C) artificial vagina. Crossbred bulls No. 36 and 37 had the highest volume of semen (4.8 ml), whereas, bull No.40 yielded the lowest volume of semen (3.9 ml). Semen volume was high during August, September, October, November and December which averaged 4.96 ml and low in the remaining part of the year (4.06 ml). Mean semen volume was higher (P